pat::LeptonVertexSignificance Class Reference

Calculates a lepton's vertex association significance. More...

#include "PhysicsTools/PatUtils/interface/LeptonVertexSignificance.h"

Public Member Functions
float	calculate (const Electron &anElectron, const edm::Event &iEvent)
float	calculate (const Muon &aMuon, const edm::Event &iEvent)
	LeptonVertexSignificance ()
	LeptonVertexSignificance (const edm::EventSetup &iSetup)
	~LeptonVertexSignificance ()

Private Member Functions
float	calculate (const reco::Track &track, const edm::Event &iEvent)

Private Attributes
TransientTrackBuilder *	theTrackBuilder_

Detailed Description

Calculates a lepton's vertex association significance.

LeptonVertexSignificance calculates the significance of the association of the lepton to a given vertex, as defined in CMS Note 2006/024

Author

Steven Lowette

Version

Id:

LeptonVertexSignificance.h,v 1.3 2008/03/05 14:51:03 fronga Exp

Definition at line 34 of file LeptonVertexSignificance.h.

Constructor & Destructor Documentation

pat::LeptonVertexSignificance::LeptonVertexSignificance

(

)

LeptonVertexSignificance::LeptonVertexSignificance

(

const edm::EventSetup &

iSetup

)

Definition at line 25 of file LeptonVertexSignificance.cc.

References edm::EventSetup::get(), edm::ESHandle< class >::product(), and theTrackBuilder_.

                                                                               {
  // instantiate the transient-track builder
  edm::ESHandle<TransientTrackBuilder> builder;
  iSetup.get<TransientTrackRecord>().get("TransientTrackBuilder", builder);
  theTrackBuilder_ = new TransientTrackBuilder(*builder.product());
}

LeptonVertexSignificance::~LeptonVertexSignificance

(

)

Definition at line 33 of file LeptonVertexSignificance.cc.

References theTrackBuilder_.

                                                    {
  delete theTrackBuilder_;
}

Member Function Documentation

float LeptonVertexSignificance::calculate	(	const Electron &	anElectron,
		const edm::Event &	iEvent
	)

Definition at line 38 of file LeptonVertexSignificance.cc.

References pat::Electron::gsfTrack(), and iEvent.

Referenced by calculate().

                                                                                               {
  return this->calculate(*theElectron.gsfTrack(), iEvent);
}

float LeptonVertexSignificance::calculate	(	const Muon &	aMuon,
		const edm::Event &	iEvent
	)

Definition at line 42 of file LeptonVertexSignificance.cc.

References calculate(), iEvent, and pat::Muon::track().

                                                                                       {
  return this->calculate(*theMuon.track(), iEvent);
}

float LeptonVertexSignificance::calculate ( const reco::Track &  track, const edm::Event &  iEvent  )

private

Definition at line 47 of file LeptonVertexSignificance.cc.

References TransientTrackBuilder::build(), edm::Event::getByLabel(), reco::Vertex::position(), funct::pow(), edm::Handle< T >::product(), mathSSE::sqrt(), TrajectoryStateClosestToPoint::theState(), theTrackBuilder_, reco::TransientTrack::trajectoryStateClosestToPoint(), and reco::Vertex::zError().

                                                                                             {
  // FIXME: think more about how to handle events without vertices
  // lepton LR calculation should have nothing to do with event selection
  edm::Handle<reco::VertexCollection> vertexHandle;
  iEvent.getByLabel("offlinePrimaryVerticesFromCTFTracks", vertexHandle);
  if (vertexHandle.product()->size() == 0) return 0;
  reco::Vertex theVertex = vertexHandle.product()->front();
  // calculate the track-vertex association significance
  reco::TransientTrack theTrTrack = theTrackBuilder_->build(&theTrack);
  GlobalPoint theVertexPoint(theVertex.position().x(), theVertex.position().y(), theVertex.position().z());
  FreeTrajectoryState theLeptonNearVertex = theTrTrack.trajectoryStateClosestToPoint(theVertexPoint).theState();
  return fabs(theVertex.position().z() - theLeptonNearVertex.position().z())
    / sqrt(std::pow(theVertex.zError(), 2) + theLeptonNearVertex.cartesianError().position().czz());
}

Member Data Documentation

TransientTrackBuilder* pat::LeptonVertexSignificance::theTrackBuilder_

private

Definition at line 45 of file LeptonVertexSignificance.h.

Referenced by calculate(), LeptonVertexSignificance(), and ~LeptonVertexSignificance().